Device for regulating an oil burner



March 15, 1966 M. FISCHBACH 3,240,255

DEVICE FOR REGULATING AN OIL BURNER Filed June 26, 1964 Ma'nfiecl FLLS cl Law/1. fl /1;,

Atty/s.

United States Patent 3,240,255 DEVICE FOR REGULATIYG AN OIL BURNER Manfred Fischhach, Altenbergstrasse 8, Neunkirchen, Kreis Siegen, Germany Filed June 25, 1964, Ser. No. 378,223 Claims priority, application Germany, July 1, 1963, F 46,119 3 Claims. (Cl. 158-38) The invention relates to a device for regulating an oil burner to which the combustion air is supplied under overpressure by a blower and the oil from an oil tank and in which the oil level is constantly maintained at the same height by means of a float. In order to maintain the required proportion of air to oil in such burners even during variation of the thermal output, the tank containing the float is connected through a conduit with the pressure or delivery side of the blower supplying the combustion air, so that a pressure prevails in the oil tank which varies in proportion with the quantity of air delivered by the blower. Since this pressure also determines the quantity of oil issuing from the oil tank, the ratio between the weight of oil and the volume of air remains approximately constant within the range of adjustment of the burner.

With burners of the kind referred to above, the oil tank must be so situated relative to the burner that the outlet position of oil from the tank is such that no oil can flow out of the tank when the blower is inoperative. This positioning of the tank also applies if the outlet from the tank is located within a pipe or riser which extends in gas tight manner from the cover or lid of the oil tank, which is in communication with atmosphere through the cover or lid, and which terminates below the oil level as determined by the float in the tank. When the blower is in operation, an oil level can be established in a riser of this kind and in conjunction with the size of the outflow orifice determines the quantity of oil issuing from the tank.

In order to avoid interdependence between the positions of the oil tank and the burner there is, according to the invention, provided a device for regulating an oil burner to which combustion air is supplied under overpressure by a blower, said device comprising an oil tank connectable with a delivery pipe and having a cover fitted thereto, a needle valve operable to control the admission of oil into the tank, a float connected with the needle valve to control operation thereof, a control pipe provided with a lateral outflow orifice and co-operating with an adapter connectable with an outlet pipe to the burner, said control pipe having the outer end thereof projecting through the cover to communicate with atmosphere, and a riser secured to the inside of the cover, said riser communicating with atmosphere through the cover, surrounding the control pipe to form an annular space therearound, and having the inner end thereof located at a position such that it is immersed in oil contained in the tank. The use of a control pipe as just specified makes it possible to mount the oil tank at an optional height above the oil burner. The quantity of oil entering the burner is determined solely by the height of the column of oil in the riser above the outflow orifice and the height of the column, in turn, depends on blower pressure, for a given caliber of outflow orifice. A device according to the invention has the advantage that on the one hand one has complete freedom concerning the positioning of the oil tank, and on the other hand, errors in positioning the oil tank and the burner housing relative to each other do not influence the quantity of fuel.

With regulating devices of the kind known prior to the invention the setting of the quantity of fuel is performed by varying the outflow cross-section. This, however, does not result in any satisfactory adjustment of the burners.

3,240,255 Patented Mar. 15, 1966 Each burner has at least one operating position for maximum thermal output and one for minimum thermal output, and it is difficult to establish equally satisfactory conditions for the two operating positions referred to, that is, to accomplish wholly soot-free combustion and to obtain a very high degree of efficiency at the same time. In view of tolerance in the manufacture of the burners, and of the varying conditions encountered on installation, each burner must be so adjusted after installation that it operates satisfactorily for the smallest quantity of heat as well as for the greatest. This, however, is not attainable or is obtainable only with great difficulty, with conventional variation of the outflow orifice, which is usually performed by means of a needle valve. This difliculty is also eliminated by a regulating device according to the invention. To this end, in a device according to the invention the outflow orifice is a hole of predetermined caliber in the control pipe, and the control pipe is axially ad justable relative to an adapter connectable with an outlet pipe to the burner.

With a regulating device according to the invention adjustment of a burner may be performed very quickly and simply. The approximate level of the outflow orifice of the control pipe is approximately fixed for use with a given kind of burner and in order to bring the burner into service, the blower is set for the minimum thermal output of the burner on the one hand, and for the maximum setting on the other, and it is possible to select the most advantageous flame image for both positions by rotating the control pipe, and then to select a middle setting which still results approximately in optimum conditions for both operating positions in the prevailing conditions of installation. Experience has shown that a very small variation in the height level of the outflow orifice suflices to vary the flame image considerably.

For adjustment of the regulating device having an outflow orifice of constant cross-section, it is sometimes important to have a higher oil level in the riser relative to the blower pressure at a given volume of combustion air. So that this may be accomplished without affecting the blower, the adaptor is provided with a collar which projects a little above the oil level determined in the oil tank by the float, and which surrounds the control pipe to form therewith an annular space. The outflow oriflee may thus be positioned below the oil level in the oil tank, so that a higher oil level than that which corresponds to the difference between the oil levels in the oil tank and in the riser is possible. i

In order that the invention may be fully understood one embodiment thereof will now be described, by way of example, with reference to the accompanying drawing wherein the single figure shows diagrammatically and in section a burner fitted with a regulating device according to the invention.

Referring to the drawing, oil is fed to a tank 1 through a pipe 2 from a storage tank, not shown, situated at a position above that of the tank 1. A float 3 in known manner controls a needle valve 4, so that oil can enter the tank 1 only when the oil level drops below a predetermined level. An adaptor 5 having an internal screw thread is fastened in the base of the oil tank 1 and an outlet pipe 6, which leads to the burner housing 7, is connected to the adaptor 5. An outlet control pipe 8 which is screwed into the adaptor 5 extends above the cover for the tank 1 and is screwed into the internal screw thread of the pipe section 5. The control pipe 8 is provided with a lateral outflow orifice 9 of a predetermined caliber. The height of the orifice 9 relative to the bottom of tank 1 may be varied by screwing the control pipe 8 into or out of the adapter 5. The adaptor 5 is provided with a collar 10 which forms an annular space around the control pipe 8 and which extends a little above the predetermined level of the oil in the tank 1 and houses a sealing ring 11 secured on the control pipe 8 to seal off the screwed connection between the adaptor 5 and the control pipe 8. The adaptor 5 and control pipe 8 control the flow of oil from tank 1 to the outflow pipe 6 and are surrounded by a riser 12 which is screwed in gastight manner to the cover of the oil tank 1 and which surrounds the control pipe 8 to form an annular space 14 therearound. The riser 12 is placed in communication with the atmosphere through a hole 13 formed in the cover. The riser 12 terminates below the predetermined level of oil in the tank 1, that is, the riser 12 is in communication with the atmosphere and its inner end is immersed in the oil in the tank.

A conduit 15 which is connected to the pressure or delivery side of a blower 16 leads in to the oil tank 1. The blower pressure thus prevails in the oil tank when the blower is in operation, so that an oil level is established in the annular space 14 between the control pipe 8 and riser 12 which corresponds to the difference between the blower pressure and atmospheric pressure. Together with the size of the orifice 9, the height of the column of oil thus formed in the riser 12 determine the quantity of oil flowing out. This oil flows into the outlet pipe 6 which is also in communication with atmosphere through the control pipe 8. As in the case of a barometric tube, a column of oil can thus form in the outlet pipe 6 the height of which is determined by the difference between the pressure in the blower 16 and atmospheric pressure, but which is not decisive in respect of the quantity of oil flowing to the burner.

As shown in the drawing, the orifice 9 may lie on the line of the float, but may lie above or below the same. The height of the column of oil above the orifice 9 may thus be varied in order to obtain the most favourable conditions in each case.

The drawing shows an overpressure burner whose housing is closed off at the top by plates 17 so that annular gaps 18 are formed between the plates, through which the combustible mixture may emerge from the burner case. The burner housing 7 fits on a pipe connector 19 which is secured to the output pipe of the blower 16.

A solenoid 21 has an armature 22 pivoted about a pin 23 and is mounted on the cover of the oil tank 1. The armature 22 carries a spindle 24, which is guided in a tube 25 secured to the cover of the tank in gastight manner. The spindle 24 terminates above an arm 20 which is fastened to the float 3. The solenoid is normally energised, that is, the spindle 24 does not act on the float 3. When the burner is switched on, that is after the blower 16 is switched on, the solenoid 21 is de-energised for a short time, the spindle 24 drops downwards and imposes a load on the float 3 through the arm 20, that is the float closes the needle valve 4 during starting up only when a higher level than the normal level has been reached. This also result in raising the oil level in the annular space 14, that is one obtains more oil during the starting up of the burner, which favours the ignition of the oil.

The use of a circular orifice 9 ensures an accurate setting for the quantity of oil required, which is reliable for protracted periods, and adjustment of the height of the control pipe 8 according to the kind of burner and the prevailing conditions of installation, may easily be performed by rotating the control pipe 8.

I claim:

1. A device for regulating an oil burner to which combustion air is supplied under overpressure by a blower, said device comprising an oil tank connectable with a delivery pipe and having a cover fitted thereto, means connecting the blower with the tank to place the tank under pressure, a needle valve operable to control the admission of oil into the tank, a float connected with the needle valve to control operation thereof, an adapter secured t9 t e bottom or the tank and arranged for connection with an outlet pipe to the burner, the adapter including a collar extending above the oil level in the tank, a control pipe screwed into the adapter for axial adjustment relative to the adapter and forming an annular space with said collar, said control pipe being provided with a lateral outflow orifice of predetermined caliber and having its outer end projecting through the cover to communicate with atmosphere, and a riser secured to the inside of the cover, said riser communicating with atmosphere through the cover, surrounding the control pipe to form an annular space therearound, and having the inner end thereof located at a position such that it is immersed in oil contained in the tank.

2. A device for regulating an oil burner to which combustion air is supplied under overpressure by a blower, said device comprising an oil tank connectable with a delivery pipe and having a cover fitted thereto, means connecting the blower with the tank to place the tank under pressure, a needle valve operable to control the admission of oil into the tank, a float connected with the needle valve to control operation thereof, an adapter secured to the bottom of the tank and arranged for connection with an outlet pipe to the burner, the adapter including a collar extending above the oil level in the tank, a control pipe screwed into the adapter for axial adjustment relative to the adapter and forming an annular space with said collar, said control pipe being provided with a lateral outflow orifice of predetermined caliber and having its outer end projecting through the cover to communicate with atmosphere, a riser secured to the inside of the cover, said riser communicating with atmosphere through the cover, surrounding the control pipe to form an annular space therearound, and having the inner end thereof located at a position such that it i immersed in oil contained in the tank, and float control means operable to impose a temporary load on the float during initial operation of the device.

3. A device for regulating an oil burner to which combustion air is supplied under overpressure by a blower, said device comprising an oil tank connectable with a delivery pipe and having a cover fitted thereto, means connecting the blower with the tank to place the tank under pressure, a needle valve operable to control the admission of oil into the tank, a float connected with the needle valve to control operation thereof, an adapter secured to the bottom of the tank and arranged for connection with an outlet pipe to the burner, the adapter including a collar extending above the oil level in the tank, a control pipe screwed into the adapter for axial adjustment relative to the adapter and forming an annular space with said collar, said control pipe being provided with a lateral outflow orifice of predetermined caliber and having its outer end projecting through the cover to communicate with atmosphere, a riser secured to the inside of the cover, said riser communicating with atmosphere through the cover, surrounding the control pipe to form an annular space therearound, and having the inner end thereof located at a position such that it is immersed in oil contained in the tank, and float control means operable to impose a temporary load on the float during initial operation of the device, said control means comprising an arm extending from the float, a spindle supported above said arm for axial movement into and out of engagement therewith, a solenoid, and an armature cooperating with said solenoid and connected with the spindle to effect axial movement thereof.

References Cited by the Examiner UNITED STATES PATENTS 2,685,917 8/1954 Perry 158-38 X 2,690,766 10/ 1954 Breese l5828 X 2,904,107 9/1959 Holthouse et al. 158-38 JAMES W, WESTHAVER, Primary Examiner. 

1. A DEVICE FOR REGULATING AN OIL BURNER TO WHICH COMBUSTION AIR IS SUPPLIED UNDER OVERPRESSURE BY A BLOWER, SAID DEVICE COMPRISING AN OIL TANK CONECTABLE WITH A DELIVERY PIPE AND HAVING A COVER FITTED THERETO, MEANS CONNECTING THE BLOWER WITH THE TANK TO PLACE THE TANK UNDER PRESSURE, A NEEDLE VALVE OPERABLE TO CONTROL THE ADMISSION OF OIL INTO THE TANK, A FLOAT CONNECTED WITH THE NEEDLE VALVE TO CONTROL OPERATION THEREOF, AN ADAPTER SECURED TO THE BOTTOM OF THE TANK AND ARRANGED FOR CONNECTION WITH AN OUTLET PIPE TO THE BURNER, THE ADAPTER INCLUDING A COLLAR EXTENDING ABOVE THE OIL LEVEL IN THE TANK, A CONTROL PIPE SCREWED INTO THE ADAPTED FOR AXIAL 